Spring flotation for center deck of draper header

ABSTRACT

A harvesting machine includes a harvesting header with a header frame, a cutterbar assembly attached to the header frame along the length thereof and configured to cut a crop, and a draper assembly positioned behind the cutterbar assembly and operable to receive severed crop material from the cutterbar assembly. The draper assembly includes a center draper that delivers crop material to a feeder house of the harvesting machine and oppositely spaced side drapers that deliver crop material to the center draper. The harvesting header is operable to flex and thereby follow an uneven terrain.

RELATED APPLICATION

This is a continuation of U.S. application Ser. No. 12/118,458, filedMay 9, 2008, which is hereby incorporated in its entirety by referenceherein.

BACKGROUND

1. Field

The present invention relates generally to a harvesting header. Morespecifically, embodiments of the present invention concern a harvestingheader with a flexible cutterbar and flexible draper conveyor.

2. Discussion of Prior Art

A traditional grain harvesting implement or machine, such as aself-propelled combine, is used to harvest a variety of grains, such aswheat, soybeans, and rice. Combines typically include a harvestingheader that cuts the crop and gathers the crop material into a feederhouse for threshing and other operations. For some grains, such aswheat, the sickle of the header can be spaced from the ground during thecutting operation. For other grains, the sickle must be positioned closeto the ground, often with the header in sliding contact with the ground,in order to collect most of the grain. Flexible headers are used tofollow the natural contours of the field while cutting the grain.

Conventional grain harvesters are problematic and suffer from variousundesirable limitations. For instance, flexible headers that include aflexible cutterbar are ineffective at receiving all of the severed cropmaterial when following the ground contour at a high speed. Prior artflexible headers are also deficient because they fail to convey all ofthe received cut crop material to the feeder house. Furthermore,harvesters with flexible headers ineffectively control the headerheight, particularly when the header is in sliding contact with theground. Yet further, prior art flexible headers become damaged whenoperating in close proximity to the ground, particularly when theterrain has a significant contour.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Preferred embodiments of the invention are described in detail belowwith reference to the attached drawing figures, wherein:

FIG. 1 is a left front perspective view of a harvesting headerconstructed in accordance with a first preferred embodiment of thepresent invention;

FIG. 2 is a left rear perspective view of the harvesting header shown inFIG. 1;

FIG. 3 is an enlarged fragmentary left front perspective view of theharvesting header shown in FIGS. 1 and 2, showing a header frame, draperarms pivotally attached to the header frame and supporting a cutterbarassembly, a left end tilt arm pivotally attached to the header frame andsupporting the cutterbar assembly and a cutterbar drive, and a left sidedraper with a draper belt of the draper assembly removed;

FIG. 4 is an enlarged fragmentary left front perspective view of theharvesting header shown in FIGS. 1-3, showing the end tilt arm pivotallymounted to the header frame and showing pivot adjustment pins attachedto the header frame to restrict pivotal movement of the end tilt armbetween uppermost and lowermost arm positions, with the illustrated leftend tilt arm being in an arm pivoting configuration and in the uppermostarm position;

FIG. 5 is an enlarged fragmentary lower right front perspective view ofthe harvesting header shown in FIGS. 1-5, showing the left end tilt armpivotally mounted to the header frame, with the left end tilt arm in thearm pivoting configuration and in the uppermost arm position;

FIG. 6 is a fragmentary left side view of the harvesting header shown inFIGS. 1-5, showing one of the draper arms in the arm pivotingconfiguration and in the uppermost arm position;

FIG. 7 is a fragmentary left side view of the harvesting header shown inFIGS. 1-6, showing the left end tilt arm in the rigid configuration andin the uppermost arm position, and showing the cutterbar drive supportedby the left end tilt arm for up-and-down swinging arm movement, with anepicyclic drive in an uppermost position relative to a rear gearbox;

FIG. 8 is a fragmentary left side view of the harvesting header shown inFIGS. 1-7, showing the left end tilt arm in the arm pivotingconfiguration and in the uppermost arm position, and showing thelaterally extending pivot location of the left end tilt arm;

FIG. 9 is a fragmentary left side view of the harvesting header shown inFIGS. 1-8, showing the left end tilt arm in the arm pivotingconfiguration and in a lowermost arm position, and showing the epicyclicdrive in a lowermost position relative to the rear gearbox;

FIG. 10 is a fragmentary left front perspective view of the harvestingheader shown in FIGS. 1-9, showing the left end tilt arm pivotallyattached to the header frame and supporting the cutterbar drive, andshowing the draper belt of the left side draper;

FIG. 11 is a fragmentary upper right front perspective view of theharvesting header shown in FIGS. 1-10, showing a crop deflector of theleft end tilt arm spaced above an outboard end of the left side draper;

FIG. 12 is a fragmentary lower right front perspective view of theharvesting header shown in FIGS. 1-11, showing the left end tilt armwith the cutterbar drive being covered by the crop deflector, showingskid plates of the cutterbar assembly, and showing an end skid of theleft end tilt arm;

FIG. 13 is a fragmentary lower left front perspective view of theharvesting header shown in FIGS. 1-12, showing the left end tilt armwith the cutterbar drive being covered by the crop deflector, andshowing the skid plates and the end skid;

FIG. 14 is a rear perspective view of the harvesting header shown inFIGS. 1-13, showing an elongated rod of the crop deflector projectingthrough an opening in an upright panel of the header frame;

FIG. 15 is a fragmentary left rear perspective view of the harvestingheader shown in FIGS. 1-14, showing a header sensing system including apair of left side potentiometers operably coupled to the left end tiltarm and one of the draper arms;

FIG. 16 is a fragmentary right rear perspective view of the harvestingheader shown in FIGS. 1-15, showing the header sensing system includinga pair of right side potentiometer assemblies operably coupled to aright end tilt arm and another one of the draper arms;

FIG. 17 is an enlarged fragmentary front left perspective view of theharvesting header shown in FIGS. 1-16, showing the potentiometer andlinkage of the potentiometer assembly interconnected with a clevisportion of the left end tilt arm;

FIG. 18 is a partly exploded perspective view of the harvesting headershown in FIGS. 1-17, showing the potentiometer and mounting bracketexploded from the header frame and from the left end tilt arm;

FIG. 19 is a schematic view of the header sensing system including thepotentiometers and a sensing circuit assembly;

FIG. 20 is a partly exploded perspective right front view of theharvesting header shown in FIGS. 1-18, showing interlocking belt guardsof the header in an overhanging relationship to a leading margin of theleft side draper;

FIG. 21 is an enlarged fragmentary side view of the harvesting headershown in FIGS. 1-18 and 20, showing the cutterbar assembly and left sidedraper, with the interlocking belt guards attached to the cutterbarassembly and extending rearwardly to overhang the side draper belt andto extend adjacent to a crop-retaining rib of the side draper belt;

FIG. 22 is a front perspective view of a pair of belt guards shown inFIG. 20, showing the belt guards in an interlocking configuration;

FIG. 23 is a cross-sectional view of the pair of belt guards taken alongline 23-23 in FIG. 22;

FIG. 24 is a rear perspective view of the pair of belt guards shown inFIGS. 20, 22, and 23, showing underlying tabs of each of the belt guardspositioned in an underlying relationship to the opposite belt guard;

FIG. 25 is a fragmentary left front perspective view of the harvestingheader shown in FIGS. 1-18 and 20-21, showing a center draper of theharvesting header spaced between left and right side drapers;

FIG. 26 is a left rear fragmentary perspective view of the harvestingheader shown in FIGS. 1-18, 20-21, and 25, showing a counterbalancemechanism of the center draper positioned adjacent to a rear end of thecenter draper;

FIG. 27 is a top fragmentary view of the harvesting header shown inFIGS. 1-18, 20-21, and 25-26, showing the sliding interconnectionbetween the center draper and the cutterbar assembly, and showing theside drapers in an overlapping relationship with the center draper;

FIG. 28 is a partly exploded right front fragmentary view of theharvesting header shown in FIGS. 1-18, 20-21, and 25-27, showing acentral guard and a reinforcing brace of the header exploded away from acentral section of the cutterbar assembly, with the central sectionbeing spaced in front of the center draper and with the central sectionextending between laterally outermost margins of the center draper;

FIG. 29 is a left side cross-sectional view of the harvesting headershown in FIGS. 1-18, 20-21, and 25-28, showing the center draper and acenter crop deflector spaced forwardly of the center draper, and showingthe center draper spaced below the right side draper, and also showingthe counterbalance mechanism of the center draper, with the centerdraper projecting forwardly therefrom;

FIG. 30 is a fragmentary side view of the harvesting header shown in1-18, 20-21, and 25-29, showing the position of the center cropdeflector relative to the center draper and relative to the right sidedraper; and

FIG. 31 is a fragmentary side view of a harvesting header constructed inaccordance with a second preferred embodiment of the present invention.

The drawing figures do not limit the present invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the preferred embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning initially to FIGS. 1 and 2, the harvesting header selected forillustration comprises a flexible header 40 and a header height sensingsystem 41. The harvesting header preferably forms part of a harvestingcombine. The header 40 is configured for cutting and collecting a cropby being advanced in a generally forward direction D so that the cropcan be fed to a feeder house (not shown) and further processed by othercomponents (not shown) of the harvesting machine to produce grain.However, at least some aspects of the present invention could be used inother machines, such as a swather or mower.

The illustrated header 40 broadly includes a header frame 42, draper armassemblies 44, end tilt arm assemblies 46, cutterbar assembly 48, anddraper assembly 50, which includes side drapers 52 and center draper 54.The header 40 also includes a central collecting auger 55 spacedrearwardly of the center draper 54 and a reel (not shown) that extendsthe length of the header frame 42 and is operable to direct upstandingcrop into the header 40. The illustrated cutterbar assembly 48 anddraper assembly 50 are preferably flexible so that the header 40 isconfigured to closely follow an undulating ground contour. However, forsome aspects of the present invention, the cutterbar assembly 48 couldbe substantially inflexible, i.e., where the cutterbar assembly 48 isrigidly mounted relative to the header frame 42. Similarly, there areaspects of the present invention where one, more or all of the drapers52,54 could be substantially inflexible relative to the header frame 42.

Turning to FIGS. 1-3, the header frame 42 preferably includes an upperbeam assembly 56 extending across the entire width of header 40, and alower beam assembly 58 that likewise extends across the full width ofheader 40. The header frame 40 further includes a number of uprightchannels 60 that interconnect beam assemblies 56,58 along the back ofheader 40 at spaced locations thereacross. Yet further, the header frame40 includes an end frame member 62 (see FIG. 20) and upright rear panels64 (see FIGS. 1 and 10) attached along the front side of channels 60.The rear panels 64 cooperatively define an upright rear wall of theheader 40, with a centrally located opening 66 (see FIG. 29) beingdefined by the rear wall and serving as a crop outlet from header 40 tothe feeder house (not shown) of the harvester machine upon which header40 is mounted. Thus, the opening 66 is spaced between left and rightsides of the header 40, when the header 40 is viewed from behind, andthe opening 66 is preferably centrally located on the header 40.

Turning to FIG. 6, the cutterbar assembly 48 broadly includes acutterbar 68, skid plates 70, and a sickle assembly 72. The cutterbar 68comprises a substantially continuous and flexible bar that extendslengthwise along substantially the entire width of the header 40 andthereby extends in a lateral direction relative to the normal directionof travel of the header 40. The skid plates 70 each comprise formedpieces of sheet metal that are secured to a lower side of the cutterbar68 and are spaced along the length of the cutterbar 68 (see FIG. 5). Theunderside of each skid plate 70 may be covered with a low frictionmaterial (e.g., a panel formed of ultra-high molecular weightpolyethylene), if desired. Preferably, the skid plates 70 are spacedapart from one another so as to permit flexing movement of the cutterbarassembly 68. In the usual manner, the sickle assembly 72 is slidablymounted on the cutterbar 68 for severing the crop. As will be discussedfurther, the cutterbar assembly 48 is operably coupled to the headerframe 42 and to drapers 52,54 to cut the crop so that severed cropmaterial falls onto one of the drapers 52,54. Furthermore, severed cropmaterial that falls onto the side drapers 52 is carried by the sidedrapers 52 onto the center draper 54, which carries crop materialrearwardly toward the opening 66.

Adjustable Cutterbar Travel Range for a Flexible Cutterbar Header

Turning to FIGS. 3-9, upright channels 60 each carry a number of armassemblies 44,46 that project forwardly therefrom, with the armassemblies 44,46 cooperatively supporting the cutterbar assembly 48 aswill be discussed in greater detail. The end tilt arm assembly 46includes, among other things, a tilt arm 74, a drive bracket 76, an endskid 78, and a spring 80. The tilt arm 74 presents opposite front andrear ends, with the drive bracket 76 and end skid 78 being attached tothe front end. The tilt arm 74 includes an arm portion 81 and a clevisportion 82 that forms the rear end and a pivot bushing 84 positionedbetween the ends. The tilt arm 74 is pivotally mounted to thecorresponding channel 60 to pivot about a laterally extending axis, witha bolt that extends through the channel 60 and the pivot bushing 84 tosecure the tilt arm 74. The spring 80 is attached to a bracket mountedto the channel 60 and the clevis portion 82 and is operable to urge therear end of tilt arm 74 downwardly in order to counterbalance loadsapplied adjacent the front end.

The draper arm assembly 44 includes a draper arm 86 with front and rearends and a spring 88. The draper arm 86 includes an arm portion 90 and aclevis portion 92 that forms the rear end, with a pivot bushing 94positioned between the ends. The draper arm 86 is pivotally mounted tothe corresponding channel 60 to pivot about a laterally extending pivotaxis, with a bolt extending through the channel 60 and the pivot bushing94 to secure the draper arm 86. The spring 88 is attached to a channelbracket and to the clevis portion 92 and is operable to urge the rearend of draper arm 86 downwardly in order to counterbalance loads appliedadjacent the front end. The illustrated springs 80,88 each preferablycomprise a hydraulic cylinder that is fluidly coupled to a hydraulicsystem (not shown) that permits the cylinder to operate as a spring(e.g., where the springs 80,88 are fluidly coupled to a gas-chargedaccumulator). However, it is also within the scope of the presentinvention where springs 80,88 include a conventional mechanical springsuch as a coil spring. As will be discussed further, the draper armassemblies 44 cooperatively support side drapers 52.

The arm assemblies 44,46 preferably are pivotally mounted andcooperatively support the cutterbar assembly 48 so that the cutterbarassembly 48 is operable to flex relative to the header frame 42 alongthe entire length thereof. However, the arm assemblies 44,46 could bealternatively constructed to permit flexing movement of the cutterbarassembly 48 (e.g., where the arm assemblies 44,46 are slidably attachedto the header frame 42 and slidable along an upright direction) withoutdeparting from the scope of the present invention. The illustratedsupporting arm assemblies 44,46 are configured to be selectively pivotalto provide flexible and non-flexible header configurations as will bediscussed. In particular, the header 40 includes threaded pins 96 andquick-release pins 98. The threaded pins 96 are each preferably securedabove the respective arm assembly 44,46 to restrict upward pivotalmovement thereof. The quick-release pins 98 are removably receivedwithin corresponding openings 100 presented by the channels 60. Theillustrated openings 100 are generally spaced forwardly of thecorresponding arm pivot axis and present a pair of pin-receivingsections that define discrete locked and unlocked locations 102,104 forreceiving the quick-release pins 98. In the illustrated embodiment, thequick-release pins 98 are preferably located below the corresponding armassembly 44,46 to restrict downward pivotal movement thereof. While theillustrated pins 96,98 are preferable, other types of pins could be usedto restrict pivotal arm movement. Furthermore, other types of stopmechanisms could be used to selectively provide limited arm movementwithout departing from the scope of the present invention. For example,the pins 96,98 could be mounted on the arm assemblies 44,46, with thechannels 60 presenting pin engaging surfaces and with pins 96 or 98being selectively positionable among locations on the arm to provideselective pivoting movement.

Each tilt arm 74 and draper arm 86 preferably comprises a single arm,but could take another form, such as a four-bar linkage as shown in U.S.Patent Publication No. 2007/0193243, published Aug. 23, 2007, entitledCOMBINE HARVESTER DRAPER HEADER HAVING FLEXIBLE CUTTERBAR, which ishereby incorporated in its entirety by reference herein.

Turning to FIGS. 7-9, the arm assemblies 44,46 are configured to shiftbetween an uppermost fixed position and a lowermost position. In theuppermost fixed position, the quick-release pin 98 can be selectivelysecured in the locked location 102 so that the arm assembly 46 is in arigid arm configuration and is restricted from pivoting, with the header40 thereby being in the non-flexible header configuration. With thequick-release pin 98 secured in the unlocked location 104, the armassembly 46 is in an arm pivoting configuration and is permitted topivot through a limited range of angular movement, with the cutterbarassembly 48 having a corresponding range of generally vertical movement,so that the header 40 is in the flexible header configuration.Preferably, the cutterbar assembly 48 has a range of vertical movementof about eight (8) inches, but it is within the scope of the presentinvention where that the range of vertical movement is greater orsmaller.

Flexible Draper and Cutterbar with Tilt Arm for Cutterbar Drive

Turning to FIGS. 10-14, each of the end tilt arm assemblies 46 ispivotally mounted adjacent to opposite ends of the header frame 42 andis supported for selective pivotal movement. As discussed above, the armassemblies 44,46 are attached to and cooperatively support the cutterbarassembly 48. The illustrated cutterbar 68 is flexible and supports thesickle assembly 72. In particular, the sickle assembly 72 comprises asplit sickle that includes a pair of flexible sickle bars 106 and knives108 that are attached to and spaced along the length of the flexiblesickle bars 106. The sickle assembly 72 also includes knife guards 110attached to the cutterbar 68, with the sickle bars 106 and knives 108being operable to slide in a reciprocating manner relative to thecutterbar 68 and flex with the cutterbar 68. The sickle bars 106preferably reciprocate in opposite directions relative to one another.However, it is within the scope of the present invention for thecutterbar assembly 48 to include a single continuous sickle bar. Again,the cutterbar 68 also supports the spaced-apart skid plates 70 thatextend below the cutterbar 68 and are configured to engage the groundand thereby cause flexing movement of the cutterbar 68.

Turning to FIGS. 8-14, the header 40 further includes a pair ofcutterbar drive assemblies 112 that are attached to respective ones ofthe end tilt arm assemblies 46 and serve to power the sickle assembly72. The cutterbar drive assembly 112 broadly includes a gear drive 114,a telescopic drive shaft 116, universal joints 118, and a forward gearbox in the form of epicyclic drive 120.

The epicyclic drive 120 includes a gear box with input and output shafts122,124, with the output shaft 124 being drivingly attached to acorresponding one of the sickle bars 106. The epicyclic drive 120 servesto offset the inertial forces of the sickle during its abruptacceleration and deceleration at opposite ends of its path of travel.While the illustrated epicyclic drive 120 is preferred, for at leastsome aspects of the present invention, another type of drive could beused to transfer power to the sickle bar 106 without departing from thescope of the present invention. Additional details of the preferredepicyclic drive 120 are disclosed in issued U.S. Pat. No. 7,121,074,issued Oct. 17, 2006, entitled BALANCED EPICYCLIC SICKLE DRIVE, which ishereby incorporated in its entirety by reference herein.

The epicyclic drive 120 is attached to the drive bracket 76 so as to befixed to the end tilt arm assembly 46 and be pivotal about a laterallyextending axis therewith. The gear drive 114 includes input and outputshafts 126,128 (see FIG. 5) and is mounted to the header frame 42 withbracket 130. The telescopic drive shaft 116 is drivingly connected tothe input shaft 122 of drive 120 and the output shaft 128 of drive 114with universal joints 118, with the telescopic drive shaft 116 extendingthrough an opening in the tilt arm 74. The input shaft 126 of gear drive114 is powered by a power take-off shaft (not shown) of the harvestingmachine. In this manner, the illustrated shaft-driven cutterbar driveassembly 112 powers the sickle assembly 72. For at least some aspects ofthe present invention, another type of transmission, e.g., a belt drive,or hydraulic drive, for transmitting power to the epicyclic drive 120and to the sickle assembly 72 may be used instead of the preferred shaftdrive of the illustrated embodiment.

The illustrated drive assembly 112 is preferably attached to and partlysupported on the end tilt arm assembly 46, with the epicyclic drive 120and telescopic drive shaft 116 being configured to pivot with the endtilt arm assembly 46. In particular, the universal joints 100 permitrelative pivotal movement between the epicyclic drive 120 and the geardrive 114. Furthermore, the telescopic drive shaft 116 permits relativelateral movement between the drives 114,120. Although the illustrateddrive assembly 112 is preferably attached to the end tilt arm assembly46, it is also within the scope of the present invention where the driveassembly 112 is attached to an inboard pivotal arm, such as one of thedraper arm assemblies 44.

In addition, the end skid 78 of the end tilt arm assembly 46 is spacedapart from the adjacent skid plate 70. In this manner, the end tilt armassembly 46 is operable to shift relative to the inboard adjacent draperarm assembly 44 while the adjacent arm assemblies 44,46 cooperativelysupport the cutterbar assembly 48. Thus, the arm assemblies 44,46 areconfigured to substantially independently pivot with the cutterbarassembly 48 when the header 40 is advanced over uneven terrain.

The illustrated orientation and configuration of the cutterbar driveassembly 112 preferably provides a substantially smooth constantrotational velocity of the output shaft 124. In particular, theepicyclic drive 120 is spaced above an axis of the tilt arm 74 and thegear drive 114 is spaced below the tilt arm axis, with the drive shaft116 extending through the tilt arm opening. The output shaft 128 of thegear drive 114 rotates at a uniform rotational velocity and drives theuniversal joint 100, which drives the drive shaft 116. However, due tothe angle between the output shaft 128 and the drive shaft 116, it hasbeen found that the universal joint 100 drives the drive shaft 116 at anon-uniform rotational velocity. In the illustrated embodiment, theinput shaft 122 of the epicyclic drive 120 is angled relative to thedrive shaft 116 at an angle α and the output shaft 128 of the gear drive114 is angle relative to the drive shaft 116 at an angle β (see FIG. 9).However, it has been determined that the illustrated arrangement ofdrives 114,120 and drive shaft 116, with the illustrated angles α, βtherebetween, the use of a universal joint 100 between the drive shaft116 and drive 120 unsubstantially cancels out any non-uniformity in therotational velocity so that the output shaft 124 provides a uniformrotational velocity. The cutterbar drive assembly 112 pivots so that theangle α lies within an angular range. Preferably, the angle β generallyfalls within that angular range so that the rotational velocity of theoutput shaft 124 remains substantially uniform as the cutterbar driveassembly 112 is operated.

Flexible Draper and Cutterbar Having Shiftable Crop Divider withDeflector

Turning to FIGS. 3, 10-14, and 25-26, the header 40 includes sidedrapers 52 and center draper 54 that are both positioned behind thecutterbar assembly 48. As will be discussed further, the side drapers 52are spaced on either side of the center draper 54 and are configured todirect severed crop material from locations along the cutterbar assembly48 to the center draper 54. Each side draper 52 broadly includesoppositely spaced inboard and outboard rollers 132,134, belt supportpanels 136, a side draper belt 138, and a belt tensioning mechanism 140.

Each of the rollers 132,134 is rotatably mounted to a correspondingdraper arm assembly 44. In particular, the inboard rollers 132 arerotatably mounted to draper arm assemblies 44 with brackets 142 andthereby extend adjacent a respective laterally outermost side margin ofthe center draper assembly 54 (see FIG. 25). The outboard rollers 134are rotatably and slidably mounted to respective draper arm assemblies44 with the belt tensioning mechanism 140. The belt tensioning mechanism140 includes slides 144 that interconnect and permit relative slidingmovement between the draper arm 86 and the roller 134 for tensioning theside draper belt 138. The rollers 132,134 are preferably mounted so asto pivot with the respective draper arm assemblies 44 about the lateralarm pivot axis.

The belt support panels 136 are elongated metal strips that extendlaterally between the rollers 132,134. The belt support panels 136 arecooperatively supported by respective draper arm assemblies 44 and serveto evenly support the weight of the side draper belt 138 and any severedcrop material on the side draper belt 138. As will be discussed ingreater detail, the side draper belt 138 is an endless belt that isparticularly configured for conveying the severed crop material towardthe center draper 54. The side draper belt 138 is rotatably mounted tosurround the rollers 132,134 and the corresponding draper arm assemblies44, with the side draper belt 138 presenting opposite endmost marginsdefined by the rollers 132,134. Furthermore, the side draper belt 138presents upper and lower runs, with the upper run extending over thebelt support panels 136 so that the panels 136 restrict the upper runfrom sagging. The lower run of the side draper belt 138 extends belowthe panels 136. The outboard roller 134 is powered by a drive (notshown), with the outboard roller 134 driving the side draper belt 138 sothat an upper run of the side draper belt 138 moves inwardly toward thecenter draper 54. While the illustrated embodiment includes left andright side drapers 52, it is within the scope of the present invention,for at least some aspects of the present invention, where an alternativeconveyor mechanism is used. For instance, multiple end-to-end sidedrapers could be used to convey crop material. Also, a conventionalauger conveyor could be used in some of the inventive aspects to conveycrop material.

Turning to FIGS. 11-14, the end tilt arm assembly 46 further includes acrop divider 146 that serves to direct crop into the header 40 anddeflect severed crop material onto the side draper 52. The crop divider146 operates as a substantially unitary structure and includes a dividerpanel 148 that presents front and rear ends, an end bracket 150 thatsecures a forwardmost tip of the divider panel 148 to an arm bracket 152of the end skid 78, and an elongated support 154 that is fastened to anunderneath surface of the divider panel 148 and extends rearwardly fromthe rear end of the divider panel 148.

The divider panel 148 also includes inner and outer walls 156,158 thatare joined along a top margin of the divider panel 148 to cooperativelyform a hollow body, with the inner wall 156 including an upright section160 and a deflector section 162 that is angled relative to the uprightsection 160. The inner wall 156 also presents a lowermost margin 164that extends between the front and rear ends of the divider panel 148.The walls 156,158 extend rearwardly from the forwardmost tip of thedivider panel 148, with the walls 156,158 cooperatively presenting agenerally expanding wall structure in the rearward direction.

The elongated support 154 includes a rod section that is shiftablyreceived in an opening 166 presented by one of the upright rear panels64. Thus, the front end of the divider panel 148 is supported by the endskid 78, with the rear end being supported by the header frame 42 sothat the rod section can pivot and slide relative to the header frame42. As the end tilt arm assembly 46 pivots up or down, the crop divider146 also pivots in the same direction.

Furthermore, the divider panel 148 is preferably positioned so that thelowermost margin 164 is spaced apart from the adjacent side draper belt138 as the end tilt arm assembly 46 pivots between the uppermost andlowermost positions. The divider panel 148 is positioned to extend overpart of the side draper belt 138 and encourage severed crop material tofall onto the side draper belt 138. In addition, the divider panel 148is spaced to permit sliding adjustment of the outboard roller 134, e.g.,for tensioning or maintenance of the side draper belt 138.

Header Height Control System with Multiple Potentiometer Input

Turning to FIGS. 15-19, the header height sensing system 41 providesfeedback to a header height adjustment system (not shown) forcontrolling the height of the header 40. The header height sensingsystem 41 includes a plurality of potentiometer assemblies 168 and anelectronic module 170 that are operably coupled to one another, with thepotentiometer assemblies 168 being operably coupled to respective armassemblies 44,46. The potentiometer assemblies 168 each include apotentiometer 172, a mounting bracket 174, and a linkage 176. In theusual manner, the potentiometer 172 includes a sensor arm 178 thatpivots to control the voltage output of the potentiometer 172. Thepotentiometer 172 is attached to a corresponding channel 60 adjacent tothe pivot of the arm assembly 44,46 using the mounting bracket 174. Thelinkage 176 directly interconnects the sensor arm 178 and the clevisportion 92, with the potentiometer 172 providing an output signalassociated with the angular position of the arm assembly 44,46. The armposition signal is also associated with the generally vertical positionof a portion of the cutterbar assembly 48 adjacent a forward end of thearm assembly 44,46. As the arm assembly 44,46 swings upwardly ordownwardly, the linkage 176 causes the sensor arm 178 to swingaccordingly, with the arm position signal, i.e., the voltage output, ofthe potentiometer 172 changing accordingly. In this manner, thepotentiometer 172 is operable to sense movement of the adjacent portionof the cutterbar assembly 48 as the header 40 moves over uneven terrain.

For each of the arm assemblies 44,46 having a potentiometer 172 to sensepivotal arm movement and provide an arm position signal, thepotentiometer 172 is preferably only coupled to sense movement of thatparticular arm. However, it is also within the scope of the presentinvention where the movement of multiple arm assemblies 44,46 is sensedby the same transducer. While the illustrated potentiometer 172 ispreferable for sensing angular movement of the arm assembly 46, it isalso within the ambit of the present invention to use other types oftransducers to sense angular arm movement, such as an angular encoder.

In the illustrated embodiment, four potentiometers 172 a,172 b,172 c,172d are preferably installed on the header 40 to sense angular armmovement of respective arm assemblies 44,46 and provide correspondingarm position signals, with two potentiometers 172 a,172 b on the leftside of the header 40 and two potentiometers 172 c,172 d on the rightside of the header 40 (see FIGS. 15 and 16). Preferably for each side ofthe header 40, one potentiometer 172 is installed to sense movement ofthe end tilt arm assembly 46 and provide a corresponding end tilt armposition signal and another is installed to sense movement of an inboardone of the draper arm assemblies 44 and to provide a correspondingdraper arm position signal. However, other sensing configurations couldbe used without departing from the scope of the present invention. Forinstance, more than two potentiometers 172 could be installed on eachside of the header 40. For example, three (3) potentiometers 172 couldbe installed on each side of the header 40, with one associated with theend tilt arm assembly 46 and two associated with corresponding draperarm assemblies 44. Furthermore, a plurality of sensors could beinstalled so that each arm assembly 44,46 has a respective potentiometer172 associated therewith, with the system 41 thereby being operable tosense the angular arm movement of all of the arm assemblies 44,46 andprovide arm position signals corresponding to the position of the armassemblies 44,46.

Turning to FIG. 19, the electronic module 170 is operable to provide anoutput signal to the harvesting machine for controlling the headerheight when the header 40 is in the flexible header configuration. Aswill be discussed, the electronic module 170 provides the output toindicate when a controller (not shown) of the harvesting machine shouldautomatically raise the header 40, e.g., by hydraulically raising thefeeder house. The illustrated electronic module 170 includes a pair ofminimum input voltage selector circuits 180. Each selector circuit 180includes a pair of buffer circuits 182 that each receive an outputsignal from the corresponding potentiometer 172, with each buffercircuit 182 including resistors 184, 186, diodes 188, and operationalamplifier 190. Preferably, the resistors 184 are 470 k-ohm resistors,the resistors 186 are 1 k-ohm resistors, the diodes 188 are 1N4004diodes, and the operational amplifiers 190 are TS9241N op amps. Theselector circuit 180 also includes selector diodes 192 electricallycoupled to the output of respective buffer circuits 182 and eachelectrically coupled to the input of another operational amplifier 194.The selector circuit further includes pull-up resistors 196 and feedbackdiode 198. Preferably, the diodes 192 are 1N4004 diodes, the operationalamplifiers 194 are TS9241N op amps, and the resistors 196 are 220 k-ohmresistors. The module 170 also includes a potentiometer circuit 200 thatis preferably coupled to all of the potentiometers 172, via common nodes202,204. The circuit 200 includes a zener diode 206 and capacitors208,210. Preferably, the capacitor 208 is a 0.1 microfarad capacitor andthe capacitor 210 is a 10 microfarad capacitor.

The illustrated arrangement of selector diodes 192 cooperatively providea selected voltage signal to the operational amplifier 194 that issubstantially the same as the lowest of the output signals received fromcorresponding potentiometers 172 by the corresponding buffer circuits182. The operational amplifier 194 provides an output signal of thecorresponding selector circuit 180 that is substantially the same as theselected voltage signal. In this manner, the selector circuit 180selects the lowest one of analog voltage signals provided by therespective potentiometers 172 and provides a corresponding selectedanalog output signal at selector output 211. However, it is also withinthe scope of the present invention where the circuit provides anothersignal, e.g., where the circuit selects the highest one of the voltagesignals and provides a corresponding signal output. Furthermore, thecircuit could provide another signal, e.g., a digital signal, thatcorresponds to a selection of one of the voltage signals provided by thepotentiometers 172.

The illustrated potentiometers 172 preferably provide an input voltageto the module 170 that ranges from about 0.5 volts to about three (3)volts based on the position of the arm assembly 44,46 and thecorresponding vertical position of the adjacent portion of the cutterbarassembly 48. In particular, the potentiometers 172 provide a voltage ofabout three (3) volts corresponding to the arm assembly 44,46 being inthe lowermost arm position and about 0.5 volts corresponding to the armassembly 44,46 being in the uppermost arm position. Again, theillustrated cutterbar assembly 48 has a range of generally verticaltravel of about eight (8) inches when the arms swing between theuppermost and lowermost positions. Therefore, vertical movement of thecutterbar assembly 48 through that range of travel causes thepotentiometers 172 to range between about 0.5 volts to about 3 volts.

The module 170 provides selected signal outputs that correspond to theposition of the cutterbar assembly 48. In particular, potentiometers 172a,172 b are operable to sense the position of a left side section of thecutterbar assembly 48 and potentiometers 172 c,172 d are operable tosense the position of a right side section of the cutterbar assembly 48.Furthermore, the selector circuits 180 each provide a selector signalassociated with the highest position of the arms corresponding torespective potentiometers 172. In this manner, the selector circuits 180each provide a single cutterbar position signal associated with thehighest vertical position of that section of the cutterbar assembly 48.

The potentiometers 172, module 170, and header height adjustment systemcooperate so that the controller of the harvesting machine automaticallyraises the header 40 when at least one of the arm assemblies 44,46pivots above a predetermined angular position. Preferably, the headerheight adjustment system controls the header 40 in response to thecutterbar position signals received from the module. Preferably, when avoltage of one of the potentiometers 172 goes below a threshold level ofabout 1.5 volts, which voltage corresponds to the cutterbar assembly 48being positioned approximately four (4) inches from the uppermostposition, the controller preferably raises the header 40. However, forsome aspects of the present invention, the output from the module 170could be used for other purposes, such as triggering a warning indicatorfor an operator.

Draper Belt with Crop-Retaining Rib

Turning to FIGS. 20 and 21, the side draper belt 138 comprises anendless belt that includes a belt body 212 and presents leading andtrailing belt margins 214,216. The side draper belt 138 further includesa plurality of fore-and-aft extending crop-engaging slats 218 projectingoutwardly from an outer surface of the belt body 212 and extendingbetween the belt margins 214,216. Yet further, the side draper belt 138preferably includes an endless crop-retaining rib 220 that projects fromthe outer surface of the belt body 212. The rib 220 includes across-sectional shape that is preferably constant along its length andtapers outwardly toward an outermost tip. Preferably, the rib 220projects at least about one-half inch from the outer surface of the beltbody 212. The crop-retaining rib 220 preferably endlessly extendsadjacent to the leading belt margin 214 so that the rib 220 is spacedbetween the margin 214 and the slats 218. However, it is also within theambit of the present invention where the side draper belt 138 isalternatively configured to carry crop material. For instance, the sidedraper belt 138 could include a plurality of crop-retaining ribs 220, orthe rib 220 could be formed in segments to present discrete ribsections.

The side draper belt 138 is rotatably received onto the rollers 132,134so as to define upper and lower belt runs 222,224, with the upper beltrun 222 operable to move toward the center draper 54. Preferably, thearm assemblies 44,46 are positioned so that the side draper belt 138slopes downwardly toward the leading belt margin 214. In this manner,any severed crop material supported on the upper belt run 222 is urgedby gravity toward the leading belt margin 214, with the crop-retainingrib 220 being configured to catch the crop material and restrict thecrop material from falling off of the upper belt run 222 until the cropmaterial is disposed onto the center draper 54.

Interlocking Belt Guards for a Draper Header

Turning to FIGS. 20-28, the header 40 further includes a flexible beltguard assembly with a central guard 226 and a plurality of interlockingbelt guards 228, with the belt guards 228 extending along the leadingbelt margins 214. Each belt guard 228 is preferably unitary andcomprises a formed piece of sheet metal that presents opposite first andsecond ends 230, 232. The belt guard 228 includes a lower flange section234, an upright section 236, and an upper overhanging section 238, allof which extend substantially from the first end 230 to the second end232. The belt guard 228 also includes a rear tab 240 projecting from theoverhanging section 238 at the first end 230 and a front tab 242projecting from the upright section 236 at the second end 232. Thecentral guard 226 and an endmost belt guard 243 also include sections234,236,238, with the central guard 226 including tabs 242, and theendmost belt guard 243 including a tab 240 on one end thereof.

The belt guards 228 are configured to be attached to the cutterbar 68 byfasteners that extend through holes in the flange section 234. Pairs ofbelt guards 228 can be mated to each other by positioning the rear tab240 of one belt guard 228 underneath the overhanging section 238 of theother belt guard 228. Furthermore, the front tab 242 of the other beltguard 228 is positioned underneath the upright section 236 of the onebelt guard 228. In this manner, each pair of mated belt guards 228 havemating ends that cooperatively form an interlocking joint so that themating ends each restrict relative up-and-down movement of the othermating end. However, the interlocking joint preferably permits relativeangular movement between mated pairs of belt guards 228 and also permitsa limited amount of relative lateral movement between mated pairs ofbelt guards 228 in the direction along the leading belt margin 214. Inaddition, the illustrated pairs of mated belt guards 228 preferably areconfigured so that uppermost surfaces presented by the overhangingsections 238 are substantially flush with one another and therebyminimize any resistance to crop flow provided by the belt guards 228.

Interlocking Belt Guards and the Crop-Retaining Rib

Turning to FIG. 21, the belt guards 228 extend rearwardly and upwardlyfrom the cutterbar 68 and extend over the leading belt margin 214. Thebelt guards 228 also preferably extend over and adjacent to thecrop-retaining rib 220. While the illustrated belt guards 228 andcrop-retaining rib 220 are slightly spaced apart, it is within the scopeof the present invention where some sliding contact occurs therebetween.In particular, the overhanging sections 238 present a downwardly facingsurface that extends in close proximity along the tip of the rib 220.Preferably, the gap between the surface and the tip is less than aboutone-quarter of an inch. In this manner, the belt guards 228 and thecrop-retaining rib 220 cooperatively form a joint that restricts severedcrop material from falling between the cutterbar 68 and the leading beltmargin 214.

Spring Flotation for Center Deck of Draper Header

Turning to FIGS. 25-30, center draper 54 serves to collect severed cropmaterial from the side drapers 52 and carry the material in a rearwarddirection toward the opening 66 and toward the feeder house of theharvesting machine. The center draper 54 broadly includes a draperchassis 244, front and rear rollers 246, belt support 248, and centerdraper belt 250. The draper chassis 244 includes a pair of side plates252 that are pivotally mounted to corresponding channels 60 and pivotabout pivot axis 254. The draper chassis 244 further includes a floorpanel 256 that is connected to and extends along a bottom margin of theside plates 252. Thus, the side plates 252 and floor panel 256cooperatively pivot about the pivot axis 254. The illustrated draperchassis 244 preferably presents a lateral width, measured from one sideplate 252 to the other, of at least about five (5) feet and, morepreferably about 6 feet, but it is also within the scope of the presentinvention where the draper chassis 244 is larger or smaller than theillustrated embodiment.

The floor panel 256 also presents a forward margin 258 that is securedto the corresponding skid plates 70 with multiple fasteners. Inparticular, the fasteners each include a rearwardly extending fingerthat is spaced upwardly from the skid plate 70 to present an elongatedslot, with the finger being attached at a forward end thereof withfasteners. The forward margin 258 is slidably received within the slotto create a sliding joint that permits relative fore-and-aft slidingmovement between the floor panel 256 and the skid plates 70 andrestricts relative vertical movement therebetween. The draper chassis244 also includes a counterbalance mechanism 260 for supporting thecenter draper 54 as will be discussed further.

The rollers 246 are rotatably mounted between the side plates 252 bymounting the rollers 246 on respective shafts 262 and by mounting theshafts 262 onto bearings (not shown) secured in the side plates 252. Thebelt support 248 is attached to the side plates 252 and is spacedbetween the rollers 246. The center draper belt 250 comprises an endlessbelt with a belt body and a plurality of crop-engaging slats 264. Thecenter draper belt 250 presents upper and lower runs 266,268. The lowerrun 268 extends below the belt support 248 and the upper run 266 extendsabove the belt support 248, with the belt support 248 being operable torestrict sagging of the upper run 266. The draper belt 250 is driven bythe rear shaft 262, which is powered by a drive (not shown) so that theupper run 266 is configured to normally move in a rearward direction andthe lower run 268 is configured to normally move in a forward direction.However, it is also within the scope of certain aspects of the presentinvention where the belt rotation direction is reversed so that theupper run 266 moves forwardly and the lower run 268 moves rearwardly(such that crop is conveyed by the lower run). While the illustratedcenter draper 54 is preferably centrally located relative to the rest ofthe header 40, it is also within the scope of the present inventionwhere the center draper 54 is located toward one side of the header 40.

Turning to FIG. 29, the counterbalance mechanism 260 serves to supportthe center draper 54 by counteracting the weight of the center draper 54about the pivot axis 254. The counterbalance mechanism 260 includes alever 270, mounting lug 272, rod 274, and compression spring 276. Thelever 270 is attached to a rear end of the corresponding side plate 252and extends rearwardly through the opening 66. The mounting lug 272 isattached to an inner wall of the adjacent channel 60 and is spaced belowthe lever 270. Adjacent a lower end thereof, the rod 274 is secured tothe mounting lug 272 and extends up through a rear end of the lever 270and through the spring 276. A stop 278 is secured adjacent to an upperend of the rod 274, with the spring 276 being captured between the rearend of the lever 270 and the stop 278. Thus, the spring 276 is operableto bias the lever 270 in a generally downward direction. The generallydownward spring force provided by the spring 276 counteracts the weightW of the center draper 54 so that the spring 276 reduces the load thatthe center draper 54 applies to the skid plates 70 and to the cutterbarassembly 48.

The center draper 54 collects severed crop material from the sidedrapers 52 by being generally spaced below the side drapers 52.Furthermore, inboard ends of the side drapers 52 overhang correspondinglaterally outermost side margins of the center draper 54 so as torestrict crop material from falling between the drapers 52,54 (see FIG.27).

Draper Head with Flexible Cutterbar Having Rigid Center Section

Turning to FIGS. 25-29, the cutterbar assembly 48 further includes anelongated brace 280 that comprises a substantially uniform length ofangle iron. However, it is also within the scope of the presentinvention to use another structure with some vertical dimension toresist bending of the cutterbar assembly 48 caused by gravity or otherloads. For instance, the brace 280 could include an L-shaped beam madefrom a material other than steel, or a beam having anothercross-sectional shape, e.g., a box shape, that serves to rigidify thecutterbar assembly 48. The brace 280 is positioned to lie on top of theflange section 234 of central guard 226 and engage the upright section236. Fasteners secure the brace 280 and central guard 226 to thecutterbar 68 and thereby define an inflexible length 282 of thecutterbar assembly 48 between ends of the central guard 226. In otherwords, the brace 280 and central guard 226 cooperatively restrict thecutterbar assembly 48 from bending along the inflexible length 282.

The center draper 54 includes laterally outermost side margins that arespaced so that the inflexible length 282 extends between the margins.The center draper 54, particularly the rollers 246, flex to only aminimal degree along the length of the cutterbar 68. Therefore, becausethe illustrated cutterbar assembly 48 is preferably rigid along theinflexible length 282, the front roller 246 and the inflexible length282 cooperatively maintain a substantially uniform spacing between aforward end of the draper belt 250 and the cutterbar assembly 48 so thatthe cutterbar 68 and center draper 54 generally move together with oneanother. In this manner, the inflexible length 282 permits the centerdraper 54 to travel over uneven terrain without parts of the centerdraper 54, such as the draper belt 250, contacting the side drapers 52and without the center draper 54 damaging itself.

Center Crop Deflector for Draper Header

Turning to FIGS. 25-30, the center draper 56 also includes a center cropdeflector 284 that is substantially unitary and is operable to directcrop material from the side drapers 52 so that crop flow from one sidedraper 52 to the other is restricted. The center crop deflector 284includes a substantially flat plate with front and rear deflectorportions 286, 288 and also includes a lower flange 290. The reardeflector portion 288 preferably presents a height 292 of at least aboutone (1) inch so that the rear deflector portion 288 resists bendingrelative to the front deflector portion 286. The rear deflector portion288 also presents a portion length 294 in the range of about one (1)inch to about six (6) inches. The rear deflector portion 288 preferablypresents upper and lower edges 296,298 that are substantially linear.The front deflector portion 286 presents an upper edge 300 that includesa lower section 302 that is substantially linear and a curvilineartransition section 304 defined between the lower section 302 and theupper edge 296 of the rear deflector portion 288.

The flange 290 of the center crop deflector 284 is attached to theforward margin 258 of the floor panel 256, with the front deflectorportion 286 extending forwardly up to the cutterbar assembly 48 and therear deflector portion 288 extending over the draper belt 250.Preferably, the rear deflector portion 288 extends over the draper belt250 a length less than half the length of the upper run 266. Morepreferably, the length of extension over the draper belt 250 ranges fromabout one (1) inch to about six (6) inches. Also, the upper edge 296 ofthe rear deflector portion 288 is preferably spaced above the draperbelt 250 a distance 306 in the range of about three (3) inches to aboutfive (5) inches. It has been determined that the illustrated length ofextension over the draper belt 250 and the height of the upper edge 296relative to the draper belt 250 permits the center crop deflector 284 todirect the severed crop material while providing minimal restriction tomaterial flow in the aft direction. In addition, the lower edge 298 ispreferably spaced above the draper belt 250 a distance less than about1.5 inches so that the center crop deflector 284 is restricted fromcontacting the draper belt 250 while sufficiently restricting cropmaterial from flowing from one side draper 52 to the other. Those ofordinary skill in the art will appreciate that such untoward crop flowis particularly problematic when cutting with only one side of theheader 40. For instance, when cutting crop only on the left side of theheader 40, the left side draper 52 will convey crop material toward thecenter draper 54. Because the right side draper 52 is conveying littleor no crop material toward the center draper 54, the crop material fromthe left side meets little resistance when reaching the center draper 54and can continue to flow past the center draper 54 and into the rightside draper 52. Therefore, the center crop deflector 284 serves toprovide sufficient resistance so that material deposited from one sidedraper 52 is restricted from flowing entirely across the center draper54 to the other side draper 52.

Operation

In operation, the illustrated harvesting header is operable to beadvanced by the harvesting machine in a field to cut the crop andcollect the severed crop material for disposal into a feeder house ofthe harvesting machine. As the header is advanced in the forwarddirection, the crop divider 146 of the end tilt arm assembly 46 definesa crop cutting path of the header and pushes crop along the sides of thepath in an inboard direction. At the same time, the cutterbar assembly48 operates to sever the crop and the reel (not shown) pushes thesevered crop material onto the drapers 52,54. Severed crop materiallocated on the side drapers 52 is carried inwardly toward and depositedonto the center draper 54. In particular, both left and right sidedrapers 52 are operable to carry any crop material inwardly, with thecenter crop deflector 284 being operable to restrict crop flow from oneof the side drapers 52 to pass over to the other side draper 52. Cropmaterial on the center draper 54 is carried in a rearward directiontoward the collecting auger 55 and is then deposited through the opening66 and into the feeder house.

The harvesting header is operable to cut and collect crop material ineither the flexible header configuration or the non-flexible headerconfiguration by configuring the arm assemblies 44,46 in correspondingarm pivoting and rigid arm configurations. The arms are placed in therigid arm configuration by positioning the corresponding quick-releasepin 98 into the locked location. With all of the arm assemblies 44,46 inthe rigid configuration, the header is placed into the non-flexibleheader configuration. In the non-flexible configuration, the header canbe advanced through the field so that the cutterbar assembly 48 anddrapers 52,54 substantially do not flex relative to the header frame 42.Furthermore, any contact between the ground and the cutterbar assembly48 will cause substantially no flexing movement of the cutterbarassembly 48 or the drapers 52,54.

Similarly, the arm assemblies 44,46 can be placed in the arm pivotingconfigurations by positioning the quick-release pin 98 into the unlockedlocation. The flexible header configuration is achieved by configuringall of the arm assemblies 44,46 in the arm pivoting configuration. Inthe flexible header configuration, the header can be advanced throughthe field so that the cutterbar assembly 48 and drapers 52,54 areoperable to flex relative to the header frame 42 between lowermost anduppermost positions. Any contact between the ground and the cutterbarassembly 48 will cause the cutterbar assembly 48 and at least one of thedrapers 52,54 to flex upwardly relative to the header frame 42, providedthat the adjacent arm assemblies 44,46 have not already reached theuppermost position. When the arm assemblies 44,46 pivot upwardly beyonda predetermined arm movement threshold between the lowermost anduppermost positions, a controller of the harvesting machine senses thethreshold condition and raises the header in response to the conditionuntil the arm assemblies 44,46 pivot downwardly below the threshold. Theflexible header configuration is particularly suited for cutting cropclose to the ground where some intermittent contact occurs between theheader and the ground.

Alternative Embodiment

Turning to FIG. 31, an alternative preferred header 400 is constructedin accordance with a second embodiment of the present invention. For thesake of brevity, the description will focus primarily on the differencesof this alternative embodiment from the preferred embodiment describedabove. The header 400 includes a header frame 402 and an end tilt arm404 pivotally mounted to the header frame 402. The header 400 furtherincludes fixed and adjustable pins 406, 408 that are attached to anupright 410 of the header frame 402. The upright 410 presents an opening412 that includes three discrete pin-receiving sections that definelocked locations 414 and unlocked locations 416,418, each of which isoperable to receive the adjustable pin 408 so that the pin can beselectively positioned in one of the locations. The unlocked locations416,418 provide two distinct lowermost arm positions that correspondwith distinct ranges of angular arm movement. Thus, the unlockedlocation 418 permits a full range of angular arm movement of the endtilt arm 404, while unlocked location 416 permits a range of movementthat is about half of the full range of angular arm movement provided bylocation 418. The locked location 414 serves to provide an uppermost armposition that corresponds with a locked arm position, with substantiallyno range of angular arm movement being permitted. Preferably, each ofthe support arms of the illustrated header 400 has a similar stoparrangement that provides similar locked and unlocked locations.

The preferred forms of the invention described above are to be used asillustration only, and should not be utilized in a limiting sense ininterpreting the scope of the present invention. Obvious modificationsto the exemplary embodiments, as hereinabove set forth, could be readilymade by those skilled in the art without departing from the spirit ofthe present invention.

The inventors hereby state their intent to rely on the Doctrine ofEquivalents to determine and assess the reasonably fair scope of thepresent invention as pertains to any apparatus not materially departingfrom but outside the literal scope of the invention as set forth in thefollowing claims.

1. A harvesting header operable to harvest a crop, said harvestingheader comprising: a header frame; a flexible cutterbar assembly mountedto the header frame to extend lengthwise in a lateral direction relativeto the normal direction of travel of the header, said flexible cutterbarassembly being operable to flex along the length thereof in response tochanges in terrain as the header is advanced; and a draper assemblysupported on the header frame behind the cutterbar assembly to flextherewith, said draper assembly including a pair of side drapers and afore-and-aft draper located between the side drapers, said side drapersconfigured to receive severed crop materials from the cutterbar assemblyand convey the materials laterally to the fore-and-aft draper, saidfore-and-aft draper being configured to move the severed croprearwardly, said fore-and-aft draper including a draper frame swingablysupported on the header frame at a pivot to project forwardly therefrom,said fore-and-aft draper including a draper belt supported on the draperframe to present a rearwardly moving run for conveying the croprearwardly, said draper frame presenting a forward margin and beingcoupled to the cutterbar assembly adjacent the forward margin such thatthe draper frame is caused to swing relative to the header frame as thecutterbar assembly flexes up and down, said fore-and-aft draperincluding a counterbalance mechanism coupled between the header anddraper frames to counteract the weight of the fore-and-aft draper aboutthe pivot so as to reduce the load of the fore-and-aft draper on thecutterbar assembly.
 2. The harvesting header as claimed in claim 1, saidcounterbalance mechanism including a spring urging the draper frameupwardly.
 3. The harvesting header as claimed in claim 2, saidcounterbalance mechanism including a pivot arm that is fixed relative tothe draper frame and extends rearwardly from the pivot, said springbeing operably interposed between the pivot arm and the header frame. 4.The harvesting header as claimed in claim 3, said spring comprising ahelical compression spring.
 5. The harvesting header as claimed in claim4, said fore-and-aft draper presenting laterally outer margins, saidcutterbar assembly being relatively inflexible along a section definedbetween the laterally outer margins of the fore-and-aft draper, whereinthe forward margin of the draper frame and generally the entirecutterbar assembly section move together as the draper frame swingsrelative to the header frame.
 6. The harvesting header as claimed inclaim 5, said cutterbar assembly including a flexible cutterbar and asickle assembly supported on the cutterbar, said cutterbar assemblyincluding an elongated rigidifying member extending along the cutterbarassembly section, said forward margin of the draper frame beingshiftably connected to the cutterbar along the cutterbar assemblysection.
 7. The harvesting header as claimed in claim 6, said rigidfyingmember comprising angle iron.
 8. The harvesting header as claimed inclaim 5, said side drapers extending laterally inward of the laterallyouter margins of the fore-and-aft draper, such that a portion of theside drapers overhang the fore-and-aft draper.
 9. The harvesting headeras claimed in claim 1; and a plurality of laterally spaced apart supportarms being attached to and cooperatively supporting the flexiblecutterbar assembly, said support arms being pivotally coupled to theheader frame for swinging movement about a laterally extending axis sothat the flexible cutterbar assembly is operable to flex.
 10. Theharvesting header as claimed in claim 9, said flexible cutterbarassembly presenting a center section defined along the forward margin ofthe fore-and-aft draper and a pair of side sections defined along theside drapers, with multiple support arms being associated with each ofthe cutterbar assembly side sections.
 11. The harvesting header asclaimed in claim 10, said support arms associated with each side sectionincluding a pair of laterally outermost support arms and at least oneintermediate support arm located between the outermost support arms. 12.The harvesting header as claimed in claim 11, each of said side drapersbeing carried on the corresponding outermost support arms and the atleast one intermediate support arm.